The present invention relates generally to a positive-electrode active material for alkaline secondary battery and an alkaline secondary battery. In particular, the invention is directed to an improved positive-electrode active material for alkaline secondary battery employing a nickel hydroxide material such that the occurrence of leakage of gas, an electrolyte solution and the like is prevented in a case where the discharged alkaline secondary battery is stored under high temperature conditions and thereafter subject to a charge/discharge process.